The document U.S. Pat. No. 5,087,949 discloses a component of the type mentioned in the introduction, in which the radiation-generating layer on the underside of the substrate has only a very small lateral extent, so that the radiation source is regarded as a point light source for the optimization of the form of the substrate. Accordingly, the substrate is shaped in such a way that the light falling onto the interfaces of the substrate from the light source from the inside is as far as possible always incident at an angle that is less than the critical angle for total reflection. What is thereby achieved is that a greatest possible part of the light generated by the radiation-generating layer is transmitted through the substrate. The optimization of the shaping of the substrate with regard to an essentially point-type light source on the underside thereof has the effect that such a substrate is only poorly suited to radiation-generating layers having a large-area extent.
The document U.S. Pat. No. 5,187,547 discloses a component of the type mentioned in the introduction, in which a radiation-generating layer applied in large-area fashion is arranged on the underside of a radiation-transmissive substrate, as a result of which the quantity of light generated overall is significantly increased compared with a point-type light source. In this case, the form of the substrate is chosen in such a way that a continuous oblique edge runs between the top side and the underside, from which edge the light is coupled out from the interior of the substrate toward the outside. The substrate side edge that is continuously bevelled from top to bottom has the disadvantage that the production of a multiplicity of such substrates from a wafer, comprising a material suitable therefor, leads to a reduced area yield of the wafer.
This is because the V-shaped incisions situated between two substrates are usually sawn using a suitable saw which, during the sawing of the substrate, leads to a not inconsiderable lateral removal of material, whereby the useable area of the individual substrates disadvantageously decreases. What is more, sawing completely through a substrate using a V-shaped saw blade is a disadvantage since the saw blade can easily be damaged in this case.